Universal joint



J 1-6, 1951 E. WILDHABER 2,538,546

I UNIVERSAL JOINT Filed Oct. 25, 1947 3 Sheets-Sheet l JNVENTOR. ERNEST W/LDHABER ATTORNEY E. WILDHABER 2,538,546

UNIVERSAL JOINT Jan. 16,1951

Filed 00%. 25, I947 Fla. 2

IN VEN TOR. ERNEST W/LDHABER BY ATTORNEY 21/,

Filed 001;. 25, 1947 Fla. .9.

Fm. 10. Z, FIG. 11. 62 so 62 ERNEST $313255 ATTORNEY Patented Jan. 16, 1951 UNITED STATES PATENT OFFICE,

UNIVERSAL JOINT ErnestWildhaber, Brighton, Y. Application October 25, 1947, Serial No. 782,078

. IO ClaimS. (Cl. 649) The present invention relates to universal joints and particularly to universal joints of the uniform'motion type, and to methods and apparatus for producing such joints. I

Universal joints. of the uniform motion type have the advantage over conventional type universal joints that they transmit motion'b'etween connected shafts at any shaft angle ,without producing torsional vibrations. Moreover, gears driven through them operate more quietly than gears driven through conventional universal joints because they eliminate the possibility of the joint setting up impulses which cause gear noise at resonant conditions. Known types'of uniform motion universal joints are, however, complicated in construction, difficult to make'l accurately, and. more costly than ordinary type universal joints. They have had, therefore only restricted use. 1

One object of the present invention is to provide a uniform motion universal joint which. can be madeaccurately at low cost.

A related object is to provide a uniform motion universal joint which can be made at 'la cost low enough to compete on a price basis even with ordinary universal joints. 1 w r Another object of the invention is to provide a low cost, high performance universal joint designed for moderate shaft angularlitiesandmarticularly suited for use in the rear-axle drives of automotive vehicles. I

A further object of the inventionis t provide a simple, fast method of producing the end. members of universal joints having the above-described features and advantages.

Still other objects of the invention are to provicle cutting and. grinding tools for quickly and accurately producing the end members of the novel joints of the present invention.

Other objects of the invention will be apparent hereinafter from the specification and from the recital of the appended claims.

In the drawings:

Fig. 1 is an axialsection showing one end member of a joint made according to one embodiment of this invention and showing in dotted lines the mating end member and showing the balls which .connect the end members;

Fig. 2 is a side elevation of the joint, the shaft angularity being the same as in Fig.1;

Fig. 3 is a fragmentary sectional view, taken transversely of one of the grooves. of one of the end members of the joint;

Fig. 4 is an end elevation of one of the end members of the joint looking at the front therebe produced in an endmember of a joint accordgrooves inan end member of a joint construct- The-hub portion of end member 20 is designated .24 has grooves 25 in its opposite sides. These section as clearly shown in Fig. 3, and are of gensuch as circle 32 (Fig, 1), which extend wholly center lines of the grooves at opposite sides of shown; disposed angulaijlyftoijone another' and Fig. 5 is a side elevation of this'end member taken at right angles to the view of Fig. 2; Fig. 6 is a transverse sectional view through the two end members of the joint when they are in axial alignment; 1 v

Fig. ,7 is a corresponding transverse sectional view through the two, end members of ajoint made according to a modification of the invention;

Figs. 8 and 9 are front and side views illustrating diagrammatically how the grooves may ing to the present invention; and

Figs. 10 and 11 area fragmentary sectional view and a fragmentary side elevation, respectively, of a face-mill jcutter made according to one embodiment of this invention for cutting ed according to theiiivention.

Referringfirst to. the embodiment of the invention shown in Figs. 1 to 6 inclusive, 20 and 2| denote, respectively,;the two end members, and 22 the balls of the joint. The two end members are identical and one only need, therefore, be described in detail. Corresponding parts of the other member will be designated by the primed reference numerals. r

In this embodiment of the invention, each end member has a hub portion and three, prongs, which project forward from said hub portion.

23 and its prongs areder'ioted at 24. Eachprong grooves are of circular arcuate shape 'in crosserally. circular arcuate shape lengthwise as shown in Fig. 1. a a

The chief novel feature of my joint is the shape of the grooves 25, 25'. The longitudinal center lines 26, 26 of these grooves are circular'arcs whose centers are'offset from the axes 28, 28' of the end members. They arearcs of circles,

to one sideof the axes 28 or 28' of rotation of the end members. They are curves which are concave towards the outside, that is, away from the axes of the end members. These curvesare inclined generally to the axes 28 and 28.. The

each prong24, 24 converge toward the fronts 3'3, 33' of the prongs, but they do not intersect axes 28, 28. They have a distance therefrom larger than the radius of balls 22. v f

.In Figs. 1 and 2, the-two endmembers are their axes 2a and 28"iiiters ectfin a point 2s.

jacent grooves. 25, of the two end members form pairs betwe'e 'i'each; of these pairs of grooves there is a ball 22. These balls engage in the grooves and transmit torque between the end members. Each ball is adapted to roll and slide lengthwise in its pair of grooves 25,25 as the joint revolves, so that the center of the ball will always be maintained at the point ofin'tersection of the longitudinal center lines 26, 26 of the pair of grooves.

The axial planes of the center lines '26; '26 and these center lines themselves intersect in the- -pl'ane l, which passes through the intersection point 29 of the axes 28, 28 and bisects theangle between these :axes. 'The axial pl'an'esand the center lines 26,28" are in other words symmetrical with respect "to plane an d o'ne can-be-consi'clered as though it were the image of the other reflected in a mirror surfaceextending along plane :30. .This is true for all turning positions of the joint. It is seen, them, that the'joint is bound to transmit uniform motion at any shaft angularity within the design-limits. =Wl1enthe joint turns on its axes 28, 28' at any given shaftangularity, the centers orthe balls 22 remain andmove in plane 3 E].

"The end members may b'e of any suitable ex- '-ternal shape. In the instance shown, the hub portion 23 of end member 25 has an external conical sur face 35,-and the end' memberis formed also with two other external conical surfaces '3'6 and =31. The apex of conical surface 36 is at the front; the apices of conical surfaces 3! and are at the rear. Surface 31 :may be made cylindrioal, if desired, especially when the end menibers are forged. Surfac'e '35 may also be made cylindrical when intended to serve as a seat for the inner race of an antifriction bearing. 7

Each side surface-of a-prong-24 comprises two planes 411 and (Fig.5) which-intersectat an 1 angle less than 180 and in aline 42.

lies ina plane perpendicular to axis 28 andpassin'g throu'gh point12'9. -Point 29 is-the anticipated This line average intersection point of axes '28, 28'. The "joint is capablefhowever, of moderate axial displacement of the end members within design limits. -The --two end members may be approached axially or separated without loss of uniformity of the transmitted motion.

--'I'he end members may be made either with even for uneven numbers of prongs. In the jointshown in Figs; 1 to -6 inclusive, the end members 20and-2I have an uneven number of prongsthre'e. Fig. 7 illustrates an embodiment of the invention in'which the two end members and '46 have an even number of prongs, namely, two. These prongs have grooves 4! and 4'1, respectively, in their "opposite sides, and the end membersare again connected by balls 48 whi'ch engage in the opposed grooves'at opjgosite'sides of the prongs of the two end memers.

For making an end member of a joint the blank oi the end member 2t, 2l, 45 or '46 may ibe first turned'or milled to'cut its outside'sur- -'face. It is then' bored and its splines '48 broached. 1

On joints with an uneven number of prongs, the surfaces 4|] at opposite sides of different prongs may lie in the same plane, and likewise the surfaces 4| at opposite sides of different prongs. Thus opposite sides of different prongs can be broached simultaneously. The plane surfaced bottoms 44 of the spacesbetween the prongs may be cut in this same broaching operation. v The sides=of a three-prongedend member may thus be completed in threebr'oaching passes.

For the cutting of the grooves 25, 25, facem'ill cutters are preferably used. .The grooves can also be ground with annular wheels, generally similar to the cutters. The operation is "substantially the same Whether the grooves be Figs. 8 and 9 illustrate a grinding operation. Here annular grinding wheels are employed that have active profiles 52 which are circular arcs that match the ciroulararcprofiles "of grooves 25, L25- The center of arc 52 Bat 53., .Preferably two wheels 50 and 51 are used so as to, be able to grind simultaneouslygrooves at-opposite :sides or the prongs of the work.

The two wheels are positioned with: their axes 54 and 55. parallel and. perpendicular to the axis 28 of 'the work, .and "with the outermost parts of their tips 2111 the same iplan'e. The wheels are rotated on their respective ax'e's in engagement with the work while the work held stationary on its axis and 'Whlle relative .depthwise feed. in the direction of axes :54 and 5.5 is effected between the wheels and. work; This feedsmovementis preferably imparted to the work. After two grooves at opposite sides of different :pron'gs of the. work have been "completed, the work may be withdrawn rapidly :from "engagement with the wheels and the work may be indexed. Then the cycle may be begunanew Ltmgrind two other groo'vesof the'work.

The shape of the grooves is applied in the end position of depthwise feed. A groove surface .is the counterpart of the active surface of the tool. iln the end position of depthwiseifeed, the center line 56 of the .circular' profiles 52 'of each grinding wheel coincides with the center line it of the groove lbeingzground andv lies in 'a plane containing the axis .2 8 of the work;

can be fed in -the direction :of .theiax'es .55 and 55 and which can be withdrawn in :this :same

direction for mounting and removing tlie work. Provision should also bemade for automatically indexing the work.

For cutting, the same general'operation-may be performed as forgrin'cllngfi-two face mill-cut- 'ters 'of circular arcuate active profile shape being simply substituted for the two "annular grinding wheels. The cutters are similar in profile shape to the grinding wheels; '=Insteadof havin 'an infinite number-of cutting edges, as have thegrinding wheels; howeven'theyhave'a plurality of cutting blades arranged circularly about their respective axes and projecting beyond 7 their side faces in the general "directionof "their "axes.

Figs. '10 and 1'1"sh'ow "a"blade-6t"of'oneform of face-mill cutter which may be employed. The

blade may be secured in conventional manner by a bolt 6! in one of the slots of the cutter head 62. The blade is recessed so that the head of the bolt does not project beyond it. This is to avoid interference with the prongs of the end member. A wedge 53 may be interposed between blade and cutter head for radial adjustment of the blade according to conventional practice.

The cutting profile 6 3 of the cutter is a circular arc which extends between end points 85, 66. The cutting profile of a face-mill cutter is the profile of an axial section of the surface of revolution described by the cutting edges of the cutter as it rotates on its axis. If the blades are sharpened so that their cutting edges lie in axial planes of the cutter, the cutting profile of the cutter is the profile of a cutting edge of the cutter. r

In the cutter shown the tangents 61, 68 at the end points of the cutting profile 64 include i an angle with each other which is less than 180 but which is larger than a right angle and amounts to at least 135. This angle is also the angle of circular arc 54. In Fig. 10, a line Hi has been drawn through profile center ll at right angles to the cutter axis. The end points 65. 66 of the cutting profile are equi-distant from said line and therefore have the same position axially of the cutter. Both points 65 and 65 are closer to the top of the cutting profile than profile center I I. They are axially in front of point H. In the preferred construction, the radius of the cutting profile 64 is less than one-tenth of the distance of the profile center H from the axis of the cutter. 62. This will cause the cutter to produce grooves whose profile curvature is suitably proportioned to their lengthwise curvature.

What is true of the cutter profile is true also of the grinding wheel'profile. The end points ,of the profile have been omitted fromFig. 9 because of the reduced scale of that figure.

The blades 69 of the cutter, are preferably sharpened by grinding back their cutting faces 13 which may be planes The blades maybe ground with a front rake or hook as is com mon practice on gear cutters. The tips and sides of the blades are relieved back of their cutting faces to provide clearance back of the cutting edges of the blades. The blades are preferably relieved axially so that the relieved surfaces, such as side surface 14, are helical surfaces of constant lead coaxial withthe cutter.

The cutter may be constructed with blades all around its periphery and a groove of the work may then be cut in a plurality of revolutions of the cutter and the cutter will then be withdrawn periodically from engagement with the work to permit indexing the work, or the cutter maybe made with blades arranged only part-way around its periphery with a gap between its last and first blades, and the work may then be indexed on each revolution of the cutter when thegap in the cutter is abreast of the work. In the latter case, the blades of the cutter are preferably made of progressively increasing height to cut progressively deeper into the work as the cut ter revolves,-and cut a groove without depthwise feed of the cutter into the work. Such a cutter can be made of large diameter and provided with both roughing and finishing blades so that a groove can be completed in a revolution of the cutter. The diameter of the cutter employed is subject to little restriction since both end members and 2| are alike.

. 6 v i In both embodiments of the invention illustrated, I have used comparatively large balls. Also I have shown grooves as deep as practically possible. This design would result in sharp edges at the inside front ends of thegrooves as at 15, Fig.5. These edges should be chamfered. Instead of chamfering by hand, these edges can be removed or chamferedwith a face-mill cutter in a separate operation from the cutting of the grooves. The axis BQof this cutter (Fig; 4) is parallel to the axis 28 of the work. The cutter cuts with its outside edges which swee in a circular path 8! and effect the desired chamferc The sharp edges 15 and the chamfer can be avgided by increasing the inclination of plane 40 (Fig. 5) so that this surface has an inclination as denoted at 401. The front end of line .401 is then as low as the chamfer would be so that a land runs all alongthe groove 25; It is also possible to cut off the hump at $2 by using a single plane in place of the two planes 4!), 41. This plane will connect the front end of plane side M31 with the rear end of plane side 4|. It may be parallel to axis 28. With this construction the end member has grooves of constant but reduced depth, the depth being equal to the depth of groove 25 at its rear end. A reduction in'groove depth is acceptable when the universal joint is to connect shafts at moderate angles. The re duced depth of groove simplifies the shape and the manufacturing process and eliminates chamfering. Y

Joints may be made according to the present invention which will compete in price with ordinary non-uniform motion joints because with the method of producing the end members of my joint, the grooves in opposite sides of a prong may be cut or ground simultaneously and fast with two face-mill cutters or annular grinding wheels. The joints are, moreover, simple in construction. v

Since a grinding wheel has an infinite number of cutting edges, the terms cutters and cuti ting as used hereinafter in the claims are intended ings in connection with an embodiment which is designed for a maximum shaft angularity of ten degrees. Such angularity is sufficient for most automotive applications. Larger angularities'can be achieved if desired by using prongs which are more out out on the sides. This may require end members of larger diameter for a given ball diameter. For larger maximum shaft angularities, as, for instance, for thirty degree angularity, the taper of the grooves, that is, their convergence is preferably increased.

It willbe understood, therefore, that while the invention has been described in connection with particular embodiments thereof, it is capable of further modification, and that this application is intended to cover any variations, uses, or adaptations of the invention following, in general, the

7 principles of the invention and including such departures from the present disclosure as come within known or customary practice in the art to which the invention relates and as may be'applied to the essential features hereinbefore set forth and as fall within the scope of the invention or the limits of the appended claims.

Having thus described my invention, what I claim is:

1. A universal joint comprising two end members, each Of which is provided with grooves ar ranged about :its axis, the opposit ends pf :said

grooves being at different radial distances fr om said axis, and balls engaging ;i-n;said grooves and connecting said end members, each of said grooves "being of arcuate profile shape and con cavely curved longitudinally away from the :axis

:of the end member.

2. A universal joint-comprising :two end mem- "bers, reach of which is -provided with grooves arranged about its axis, 'theopposite ends of said grooves being at different radial distances from 'saidaxis'ancl ballsengaging in said grooves and connecting saidend members each of said: grooves being of arcuate profile shape and concavely curved longitudinally away from the axis of the -:end;member, the center line of each groove lying :in a :plane containing the axis of its end :member.

13. Anniversaljoint comprising two end memibers, -each of which is provided with groovesari ranged about its axis, the oppositeends of said grooves-being at *difierent radial distances :from saidaxia-and balls engaging in said grooves and connecting saidzendmembers, each ofsaid grooves being of circular arcuate profile shape .and being lcurved longitudinally awayfrom the axis of- .the

end member along a :concave circular arc, the

center line of each groove lying -in.a plane con- :taining theaxis of its end member.

' '4. A universal joint comprising two end .memhere, which are provided with'oppositely inclined members, the grooves in "the two end members being oppositely inclined and eachgroove being concavely curved longitudinally away from the axis of its end member and having its opposite ends at difierent radial distances .from the axis of -i-ts;end;member.

Aiuniversal joint comprising two end members, eachof which is provided with a plurality of :prongs, each of said prongs having longitudi- ,nally curved grooves at its opposite sides which are open at bothrendszand which converge toward the front of the prong, said grooves being of ,arcuate profile shape and ,concavely curved longitudinally away from the axes of their respective :end:me.mbers, the grooves in the :two end =mem- Ebers being {oppositely inclined, gtheprongs of one sendimemherinteriittin with prongs 0f theother end member, and balls engaging in the opposed grooves ofrtheprongs to transmit torque between the end members. i

19.. ;A alniversaljoint comprising two end mem- -bers,each of which is provided with a plurality grooves, and balls-engaging in said grooves and connecting said end members, each of said grooves having its opposite ends at difierent radial distances from the axis of its end member and being of circular ,arcuate profile, shape and being :curved longitudinally along an arc of a circle Whose plane passes through the axis of its end member and whichjlies whollyjat one side of said axiswithout crossing it.

,5. A universal joint comprising Itwo end members, each of which is provided with aplurality of grooves, and balls engaging .in said grooves and connecting said end members,-th e grooves of each. end ,member lconvergi'ng'toward the front of the end member, and 'thejgroo'ves OfthetWO end members beingoppositely inclined, each 'of said grooves being concavely curved longitudinally away from the axis of its end'member.

.6. 'A-universal joint comprising two'end'members, each of which is provided ith aplurality of grooves; and balls of equal size engaging in .saiidgrooves and connecting said endmembe'rs,

the grooves of each end member "converging toward the front 01 the end 'member, and the grooves of thetwo end members being oppositely oppositely inclined; the prongs of one end memof :prongs'each of said prongs having grooves .atiits opposite sides which are open at :both ends and which are ;curved longitudinally along circular altos which converge towardthe front of-the prong :and which are closer to the axis of the encl'member at the front-of the prong than at the rear athereohsaid:grooves being of arcuate profilezshape rand eoncavely curved longitudinally .-away;irom:the axescf-theirrespective end mem- -bersgthegrooves in the two end members being :berlinterfitting with the prongs of the othe end member, and balls engaging in the opposed grooves i of the prongs to transmit torque-between "the endmembers.

10. A universal joint comprising two endmemhers, each of which :has :three prongs, each of .'-said gprongs having grooves of circular arcuate "profile :shapefformed ,in its opposite sides, which are open at both :ends :and which are curved glongitudinally away from the axis of the end :member along ;a concave circular arc, :the L prongs of one member ;interfittin with the prongs of theother end :mcmberand the opposed grooves in :the prongs :of the two end -members forming pairs anda balllrengagingjin the two grooves of each pairgthe center line of each groove being an arcxof a circle whose :plane passes through the axisofzitsendim-ernberand whichextends wholly Number atone "side of saidraxis ata distance therefrom larger than the radius. ofi-theball.

ERNEST WILDHABER.

V REEEBENGES GITED V Thefollowing references are of'record in-the "file-of this patent:

,UNIIED STATES PATENTS Name Date -3Scott V May 10, 1927 Weiss July 1, 1930 aBill j s Apr; 25, 1939 Aber Mar. 28, 1944 Duservoir Nov. ,7, 1944 pK-rausnann Jan. 16, 1945 Seiter Aug. 14, 1945 

